This disclosure relates generally to providing assistance for displacing a tubular string and, in one example described below, more particularly provides a way of urging a tubular string to displace in a subterranean well.
It is sometimes desirable to displace a tubular string through a restricted space (such as a wellbore, pipeline, etc.). If the restricted space is horizontal, or at least substantially inclined, then friction can impede displacement of the tubular string through the inclined or horizontal space. In other situations (for example, where a tubular string is relatively flexible), it can be difficult to push the tubular string through a restricted space.
Therefore, it will be appreciated that improvements are needed in the art. Such improvements may be useful whether or not a restricted space in which a tubular string is to be displaced is horizontal or substantially inclined, and whether or not the tubular string is relatively flexible.